Set status to 'not-busy' when server startup is complete

[MichaReiser]

Summary

Ensures that the extension calls updateStatus with busy=false when the server startup is complete.

This is now necessary after #600 correctly added an updateStatus call with busy=true before the server starts.

Fixes #605

Test Plan

I ran the extension and verified that the busy indicator no longer spins forever.

[dhruvmanila]

I'm confused, where did #600 add the updateStatus call? I think that PR only changed the ordering such that the disposables are added only after a successful server start.

[MichaReiser]

Hmm good call. I have to look into this again what the root cause is for it breaking

[dhruvmanila]

The bug was that the onDidChangeState handler was being added after the server started so when the client updated the status to running, the handler wasn't present which would've changed the status. I've pushed a commit that changed the order back and added a helper function to dispose and remove them from the array and is being used when (a) the server failed to start or (b) when stopping the server.